Portable smoke measuring device

ABSTRACT

A portable device for visual measurement of smoke density of opacity that includes first and second discs that are support in overlapping relation for rotation relative to each other. Each disc has means effecting the opacity of light passing therethrough with the two means cooperating to vary the opacity of the selected area of the disc in response to angular rotation of the discs relative to each other. The device has indicating means giving an indication of the degree of opacity of the selected area so that the selected area may be located in juxtaposed relation to a stream of smoke emanating from a stack and the discs can be rotated relative to each other until the opacity of the selected area corresponds to the opacity of the smoke. In one embodiment, the discs are of the exposed photosensitive plate type and have a peripheral area of progressively increasing opacity that are placed in overlapping relation to vary the opacity of the two discs while in the alternate embodiment the discs are polarized so that relative rotation will decrease the amount of light passing therethrough.

359*40? Lag X9 -3 a 779 9 5 t: Crowley [54] PORTABLE SMOKE MEASURING DEVICE [76] Inventor: John H. Crowley, 5607 Alburg Ave., Racine, Wis.

[22] Filed: June 25, 1971 [21] Appl. No.: 156,612

Primary ExaminerDavid Schonberg Assistant ExaminerConrad Clark A!t0rneyMax Dressler et al.

Dec. 18, 1973 57 ABSTRACT A portable device for visual measurement of smoke density of opacity that includes first and second discs that are support in overlapping relation for rotation relative to each other. Each disc has means effecting the opacity of light passing therethrough with the two means cooperating to vary the opacity of the selected area of the disc in response to angular rotation of the discs relative to each other. The device has indicating means giving an indication of the degree of opacity of the selected area so that the selected area may be located in juxtaposed relation to a stream of smoke emanating from a stack and the discs can be rotated relative to each other until the opacity of the selected area corresponds to the opacity of the smoke. In one embodiment, the discs are of the exposed photosensitive plate type and have a peripheral area of progressively increasing opacity that are placed in overlapping relation to vary the opacity of the two discs while in the alternate embodiment the discs are polarized so that relative rotation will decrease the amount of light passing therethrough.

5 Claims, 6 Drawing Figures SEARCH, ROOM- PATENTEDUEC 18 ms 3,779,650 SHEET IN 2 NVE NTOR JOHN H. CROWLEY ATTORNEYS PORTABLE SMOKE MEASURING DEVICE BACKGROUND OF THE INVENTION The present invention relates generally to air pollution control and more particularly to an improved portable device for visual measurement of smoke density or opacity.

For many years visible smoke emissions from power plants, industrial plants, and engines have been considered a sign of noxious pollutants entering the atmosphere or creating an aesthetic nuisance. In recent years, federal, state, and local government bodies have passed laws limiting the density of smoke emanating from smoke stacks and other smoke producing sources.

In order to control the amount of smoke pollution being created by a given source, various types of measuring devices have been utilized in determining the density of the smoke. One of the most common type of devices utilized in connection with measuring smoke density is the Ringelmann type chart. One kind of Ringelmann chart consists of a peripheral area that surrounds an opening with the area being divided into segments. Each segment has a degree of blackness that corresponds to a percentage-density of total or 100 percent blackness. The Ringelmann type chart is used by positioning the smoke emanating from the stack in the open center of the chart. The smoke is then compared with the various areas surrounding the opening and the one most nearly corresponding to the shade or density of the smoke will indicate the percentageblackness of the smoke being observed. Usually the Ringelmann type chart is divided into five segments that progressively vary from percent black to 100 percent black and the respective segments are so numbered, In many instances statutes limiting the density of smoke will define the maximum blackness in terms of a Ringelmann number.

There are several disadvantages of the Ringelmann chart, the primary ones being that it requires a subjective judgment by the inspector and is very sensitive to background light and reflection. In addition, there is a large gap between the respective adjacent segments with respect to the percentage-density of the two adjacent segments thereby requiring interpolation. Furthermore, the density of the smoke being measured is dependent upon a comparison of the smoke density with the chart blackness and the blackness of the corresponding segments may vary from one unit to another depending upon the manner in which the chart was manufactured.

Another type of device that has found a considerable measure of use in measuring smoke density, especially of engines, is the full-flow direct-reading smokemeter which consists of a light source and a photoelectric cell that are mounted a few inches from the open end of the exhaust pipe or stack on opposite sides of the smoke plume so as to continuously measure the amount of light obscured by the smoke plume. The output of the photoelectric cell is read remotely on a meter or stripchart recorder in terms of either light transmission or light obstruction.

While these devices can give a rather accurate reading, it will be appreciated that it is necessary for the light source and photoelectric cell to be located in close proximity to the open end of a smoke stack or other smoke emanating structure. Thus, such devices are completely unsatisfactory for secret detection of the density of smoke emanating, for example, from an exhaust stack of a vehicle moving along the highway.

Since most of the concern is with black smoke that consists of very small soot (mainly carbon) particles, another manner of determining smoke density is to filter the particles from the fluid and accurately measure the amount of particle removed from a given volume of fluid. An alternative method is to utilize a lightdispersion smokemeter such as that developed by the Robert Bosch Corporation.

While the latter units discussed above can give a rather accurate reading of smoke density, they require ready accessibility to the smoke stack since they are dependent upon having smoke flowing through or into the unit in some manner.

SUMMARY OF THE INVENTION The present invention contemplates a portable inexpensive smoke density measuring device that can determine the density in a matter of seconds while eliminating the need for being in close proximity to the column of smoke being measured. The device may be categorized as a visual or comparator method of determining relative smoke density.

The device consists of first and second discs that are supported in superimposed relation to each other for relative rotation with respect to a center axis with each of the discs having means that effect the opacity of light capable of passing therethrough. The means on each disc cooperate with each other to vary the opacity of at least one selected overlapping area of the discs in response to rotation of the discs. The device further includes support means for maintaining the discs in overlapping relation to each other and has means for rotating the discs relative to each other about their common axis as well as indicator means giving an indication of the degree or percentage of opacity of the selected area so that the selected area may be placed in juxtaposed relation to smoke emanating from a source and the discs rotated relative to each other until the opacity of the selected area corresponds to the opacity of the smoke. This will result in giving a direct reading of the percentage or degree of opacity of the smoke or the density of the smoke.

In one embodiment of the invention, the discs are exposed photosensitive plates and the means on each disc is in the form of a peripheral area of circumferentially varying opacity so that the peripheral areas of the respective discs may be overlapped and relative rotation of the two discs will vary the opacity of the selected area of the discs. In an alternate embodiment, the discs are polarized so that relative rotation of the discs will decrease the opacity of light through the discs in the selected area. In one form of the invention, the portable smoke measuring device has an opening through the center thereof with the smoke to be measured being positioned in the opening while the selected area completely surrounds the opening in the center to allow more accurate visual observation of the degree or percentage-density of the smoke being measured.

While the support means for holding the discs in superposed relation may take many forms, two types of support means have been illustrated in the drawings and will be described in more detail hereafter.

The smoke measuring device of the present invention eliminates the need for interpolation between fixed chart blackness levels, such as is found in the Ringelmann type chart, and eliminates the effects of distance of the chart from the eye, as well as the attitude of the chart and reflections of the face of the chart. The device also permits the measurement of smoke from large and inaccessible sources, such as industrial smoke stacks and ships without interfering with the operation of the sources or without knowledge of the operators of the sources. In addition, the device permits a more accurate reading of apparent smoke density since that unit will measure a density relative to the surrounding atmosphere. For example, if the surrounding atmosphere is not completely clear, the measurement will automatically compensate for the density of the surrounding air.

DETAILED DESCRIPTION OF SEVERAL VIEWS OF DRAWINGS FIG. 1 shows the portable device as it would be positioned relative to a plume of smoke emanating from a stack;

FIG. 2 shows an exploded perspective view of the various elements forming the unit shown in FIG. 1;

FIG. 3 is a plan view of one of the discs utilized in the smoke measuring device;

FIG. 4 is an exploded perspective view of a slightly modified form of the invention;

FIG. 5 is a plan view of one of the discs utilized in connection with the embodiment of the invention shown in FIG. 4; and

FIG. 6 shows the modified form of the invention as it would be utilized in measuring the density ofa plume of smoke emanating from a stack.

DETAILED DESCRIPTION While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail two specific embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. I

Referring to FIG. 2 of the drawings, there is shown the several elements that form the portable smoke density measuring device 10. The device 10 consists of first and second discs 12 of substantially identical construction. Each of the discs has means effecting the opacity of light capable of being passed therethrough. For this purpose, the discs 12 are of the exposed photosensitive plate type and each has a peripheral area that has a maximum degree of opacity at 14 and progressively decreases to a minimum degree of opacity at 16. The device further includes support means for maintaining the discs in overlapping relation to each other and accommodating relative rotation of the respective discs. In the illustrated embodiment, the support means is in the form of a cover consisting of first and second plates and 22 each having an axially extending flange 24 and a recess 26 extending from the peripheral edge of the circular plate. In addition, the plate 20 has a circumferentially extending slot 28, for a purpose which will be described later. The support means further includes a stationary block 30 located between the two discs 12 and the portable device has drive means for rotating the discs relative to each other. In the illustrated embodiment of FIGS. 1 and 2, the drive means is in the form of a beveled gear 32 on each of the discs 12 and a drive gear 34 as well as a driven gear 36 that respectively engage the beveled gears 32. The drive gear 34 is capable of being rotated about a fixed axis through a stub shaft 38 having a knob 40 on the end thereof while the driven gear is supported for rotation by a stub shaft 41. The disc plates and drive mechanism are held in an interconnected relation by a pin 42 that extends through openings 44 located in the center of the block 30 as well as the cover plates 20 and 22.

The only remaining feature of the combination is the indicator means that gives an indication of the degree or percentage of opacity, in a manner that will be described later. The indicator means is in the form of a ring 46 defined along the inner edge of the peripheral area of progressively increasing opacity of one of the discs and in its assembled condition numerical values 48 are in alignment with the circumferential slot 28. The cover has an arrow A adjacent the slot.

In assembling the smoke measuring device 10, the driving and driven gears 34 and 36 are positioned on the stationary block 30 and the two discs are located on opposite sides of the blocks with the respective beveled gears 32 in meshing engagement with both of the gears 34 and 36. The outer cover plates 20 and 22 are then located on opposite sides of the discs with the recesses 26 aligned with each other to define an exposed area of the disc. The pin is then inserted through the apertures 44 so that the entire unit will be held in assembled condition with the gears 34 and 36 in meshing engagement with the bevel gears 32. In the assembled condition, the indicator ring 46 is in alignment with the elongated circumferential slot 28 so that the numbers 48 appearing on the indicator ring are visible through the slot. In the assembled condition, the recesses 26 define a selected overlapping exposed area of the discs or a guide window.

In using the device, the guide window is located in juxtaposed relation to smoke emanating from a source, such as a smoke stack, and the discs are rotated opposite directions relative to each other by the knob 40 and driving gear 34. When the window area, defined by re cesses 26, has a degree of opacity that corresponds to the opacity of the plume of smoke 5 emanating from the stack 49, the operator need only take a reading of the numerical value aligned with the arrow A adjacent the slot 28 which will give the operator the density or degree of opacity of the plume of smoke.

The advantages of the visual comparison over that of the Ringelmann type chart are numerous. One of the principal advantages is that the unit is not subjective to ambient light reflections or changes in printers ink density, such as the Ringelmann chart.

In the embodiment of the invention, shown in FIGS. l-3, the two discs are exposed photosensitive plates each having an increased degree of exposure around the periphery thereof accurately calibrated as to opacity by a photocell light meter or optical densiometer. For example, the opacity of each of the discs will be at a minimum or zero at the area 14 and a maximum or approximately one-half of the opacity scale rating on the ring 46 at the opposite end 16 of the peripheral area of progressively increasing opacity. The opposite disc 12 would likewise have minimum and maximum degrees of opacity l4 and 16 but the positions of the two are reversed. For example, the opacity on each disc will vary circumferentially from 0 to 50 percent between opposite ends of the peripheral area.

A slightly modified form of the invention is disclosed in FIGS. 4-6 and will now be described. The modified form of smoke measuring device 60, shown in exploded view in FIG. 4, again includes two discs 62 and 64 that have means thereon effecting the opacity of light passing therethrough. In the embodiment illustrated in FIGS. 4-6, the discs 62 and 64 are polarized discs that are held in overlapping relation to each other by the support means in the form of a first ring or plate 66 having a flange 68 extending from the inner edge thereof that is adapted to extend through apertures 70 defined in the center of the respective discs 62 and 64. The ring 66 cooperates with a second ring or plate 72 to define ring or plate means for maintaining the discs 62 and 64 in overlapping relationship and accommodating relative rotation about their common axis. As in the previous embodiment, the device includes means for rotating the discs relative to each other which is in the form of an integral tab 75 that extends from the periphery of the disc 64. The smoke measuring device 60 also includes indicator means in the form of a numerical chart 76 defining percentage opacity on an integral extension 78 of the disc 62. An arrow 80 is produced on the exposed surfaces of the disc 64.

The modified device 60 is operated in a substantially identical manner to the one described above. The device is positioned such that the central aperture 82 in the ring means has the plume of smoke emanating from the stack positioned therein and the area of the respective polarized discs surrounding the aperture 82 has the background positioned therein. Thus, the exposed area of the polarized discs completely surrounds the aperture. The disc 64 is then rotated relative to the disc 62 until such time as the apparent opacity or density of the tages over previously known comparison type devices that did not require direct access to the smoke being V measured. The device can measure the density of background as seen through the surrounding area of two discs corresponds with the opacity or density of the plume of smoke as seen through the central aperture 82. The operator then reads the percentage of opacity aligned with the arrow 80 to get an accurate determination of the acutal density of the smoke emanating from the stack 49. In both embodiments, it is desirable to take the reading directly above the stack 49.

As can be appreciated from the above description, the present invention provides a simple and inexpensive smoke measuring device that has numerous advansmoke emanating from a stack in a matter of seconds since it requires no setup or teardown time prior to and after making the inspection. The device could readily be carried by an inspector and upon seeing smoke emanating from a stack, a quick and accurate reading could be made without the necessity of being next to the smoke stack.

I claim:

1. A portable device for visual measurement of smoke density or opacity comprising first and second discs substantially coextensive in demension; plate means engaging opposite surface of said discs for maintaining said discs in coaxial and overlapping relation to each other and accommodating rotation of said discs relative to each other, holding means extending through said discs for holding said plates in assembled relation, each disc having circumferentially varying opacity, said discs cooperating to vary the opacity of at least one selected overlapping area of said discs, the degree of opacity of said selected area being dependent upon the angular position of said discs; means for rotating said discs about their common axis relative to each other; and indicator means giving an indication of the degree of opacity of said selected area so that said selected area may be located in juxtaposed relation to smoke emanating from a source and the discs rotated relative to each other until the opacity of the selected area corresponds to the opacity of the smoke.

2. A device as defined in claim 1, in which said discs are polarized discs.

3. A device as defined in claim 1, in which said discs have a central aperture with the smoke to be measured being positioned in said aperture and said selected area surrounds said aperture.

4. A device as defined in claim 1, in which said discs are exposed photosensitive plates.

5. A device as defined in claim 1, in which said means for rotating includes circumferential gear means on adjacent surfaces of said discs, a stationary support block between said discs and a drive gear rotatable on said block and in mesh with said gear means. 

1. A portable device for visual measurement of smoke density or opacity comprising first and second discs substantially coextensive in demension; plate means engaging opposite surface of said discs for maintaining said discs in coaxial and overlapping relation to each other and accommodating rotation of said discs relative to each other, holding means extending through said discs for holding said plates in assembled relation, each disc having circumferentially varying opacity, said discs cooperating to vary the opacity of at least one selected overlapping area of said discs, the degree of opacity of said selected area being dependent upon the angular position of said discs; means for rotating said discs about their common axis relative to each other; and indicator means giving an indication of the degree of opacity of said selected area so that said selected area may be located in juxtaposed relation to smoke emanating from a source and the discs rotated relative to each other until the opacity of the selected area corresponds to the opacity of the smoke.
 2. A device as defined in claim 1, in which said discs are polarized discs.
 3. A device as defined in claim 1, in which said discs have a central aperture with the smoke to be measured being positioned in said aperture and said selected area surrounds said aperture.
 4. A device as defined in claim 1, in which said discs are exposed photosensitive plates.
 5. A device as defined in claim 1, in which said means for rotating includes circumferential gear means on adjacent surfaces of said discs, a stationary support block between said discs and a drive gear rotatable on said block and in mesh with said gear means. 